The New England Complex Systems Institute has become the latest organization to charge that by turning almost 50 percent of our corn crop into auto fuel, America is causing food shortages in the poorer nations of the world. The UN Food and Agriculture Association has been saying the same thing for ten years, calling biofuels "a crime against humanity." But this time the authors are not simply making the accusation. They are providing correlations to back it up.

The statistical argument is in the accompanying graph. The study by Dr. Yaneer Bar-Yam and two co-authors shows that recent rioting and political unrest has been concentrated during brief periods when world food prices were at their peak. The blue curve running left to right shows the world food price index from 2004 to the present. (The insert at upper left shows the same index since 1990.) The vertical red lines pinpoint incidents where there have been large-scale riots against governments in the developing world. The number in parentheses is the death toll during the incidents.

There was a huge peak in early 2009 after food prices had almost doubled over the course of one year. The trend subsided when the index declined over the next two years but re-emerged in 2011 when it peaked again. The latter outbreak includes much of the “Arab Spring,” which started in Tunisia and spread to most of North Africa and the Middle East. But it also includes riots in Mozambique and Uganda, which are not Arab countries. Interestingly, the authors do not even include the "Taco Riots" in Mexico at the 2009 peak, apparently because they consider Mexico a fully developed nation.

Of course correlation is not causation and it could be argued that the Arab Spring was the result of long political repression rather than food prices. But the authors argue that even autocratic governments can maintain their legitimacy as long as they are able to provide basic necessities. “When the ability of the political system to provide security for the population breaks down, popular support disappears.”

The authors provide a “threshold price” beyond which they say civic unrest is likely to occur and argue that the drought in the western United States pushed food prices over that threshold once again last year. At the same time there was unprecedented labor union violence in South Africa and food-related protests in Haiti and Argentina. With regard to South Africa, the authors write: "Worker demands for dramatic pay increases reflect that their wages have not kept up with drastic increases in the prices of necessities, especially food."

Complexity studies attempt to harness high-powered computers to track the course of change among intricate social phenomena. The Santa Fe Institute has long been the home of complexity studies but other institutions are starting to pop up around the world as well.

As to the question of whether the United States should be diverting half the corn crop to auto gas tanks, the American political system remains completely oblivious to the issue. Biofuels are still regarded as a trendy, earth-friendly undertaking with little or no regard to their impact on world food supplies. This week President Obama announced another major effort to advance research on alternative fuels that will include further development of biofuels. Of course this time the major target is to develop cellulosic ethanol, which would involve “plant wastes” instead of the food portion of corn and other crops. That could make the situation better. On the other hand, if it expands the overall market for biofuels, it could end up making things worse.